The fundamental problem with immersion treatment installations which operate with a conveyor system which has one or more transport carriages and can essentially be operated continuously relates to how the object to be treated can be lowered from the transport position, in which it is at a height above the level of the treatment fluid, so that it is fully immersed in the treatment fluid. To this end, various solutions are proposed:
In the immersion painting installation described in DE 196 41 048 C2, the conveyor system is designed so that the objects to be treated are immersed in, and removed from, the baths by superimposing a purely translatory movement and a purely rotational movement about an axis aligned perpendicularly to the transport direction. The axis of rotation here has to be relatively far outside the contour of the vehicle body and therefore far from its centre of gravity. In the case of objects which are very heavy, this requires highly complex holding points due to the very high forces produced. Moreover, only single kinematics are possible during the immersion and removal of the objects. Finally, immersion painting installations of this type have a relatively large spatial requirement in the vertical direction.
In the immersion painting installation known from DE 101 03 837 B4, each transport carriage comprises a pivot arm which can be pivoted at one end about a first axis of rotation moving with the transport carriage and which, at the other end, by way of a second axis of rotation, carries the fastening device to which the object to be painted is fastened. The movement by which the vehicle body is immersed in the immersion tank here can be seen as a superimposition of two rotational movements about the two said axes of rotation and a translatory linear movement in the horizontal direction. Much of the vertical movement here is generated from the pivotal movement of the pivot arm. This known immersion painting installation has an extraordinarily high variability in terms of the achievable movement kinematics as well as good flexibility. Nevertheless, it involves a certain degree of expenditure on apparatus.
An immersion treatment installation of the type mentioned at the outset is finally known from DE 20 2008 017 770.
In this, the carrying platform to which the vehicle body to be painted can be fastened can be moved in the vertical direction by way of a skid. The overall movement can be seen here as a superimposition of a linear movement in the translatory direction, a linear movement in the vertical direction and a rotational movement about the axis of rotation. The vertical movement is effected by a motor; the connecting structure between the object and the carrying platform is intrinsically rigid.